DESCRIPTION: This is a Phase II proposal to study chemical compounds which will elevate transcription of the human fetal gamma-globin gene. The significance and relevance of this proposal is that sickle cell disease and beta thalassemia would be markedly ameliorated if gamma-globin gene expression could be stimulated such that 25-30% of the circulating hemoglobin was fetal hemoglobin. During phase 1 of their studies, they successfully established cell lines and reagents required for drug screening and follow up. Initial screening of 10,400 fungal extracts identified 26 samples which induced gamma gene expression with no effect on the transcription of other genes tested. During Phase II studies, they propose to continue high-throughput screening against the K562/HS2-gamma globin reporter cell line and a second screen will be implemented in which the luciferase reporter gene will be inserted at the gamma position within the entire human beta-globin locus. Using robotic screening systems developed by this laboratory, they plan to screen a large file of more than 100,000 chemical compounds and 50,000 fermentation broth extracts to search for substances which will enhance gamma-globin synthesis. Lead compounds identified in the screen which induce gamma-globin transcription will be examined for potency, specificity and activity in human erythroid cell tissue culture models (K562). Ultimately, in Phase III studies, lead compounds will be evaluated in animal models of human sickle cell disease prior to pharmacokinetic and toxicological evaluation and clinical development.